Modern optical devices and optical communications systems widely use fiber optic cables. Optical fibers are strands of glass fiber processed so that light beams transmitted through the glass fiber are subject to total internal reflection wherein a large fraction of the incident intensity of light directed into the fiber is received at the other end of the fiber.
Many approaches to achieve fiber alignment can be found in the prior art, among them are V-grooves and ferrules. Ferrule based alignment systems including include ferruled connectors which use cylindrical plugs (referred to as ferrules) that fit within an alignment sleeve (e.g., a cylindrical split sleeve with elastic characteristics) to perform fiber alignment. Precision holes are drilled or molded through the centers of the ferrules. Optical fibers are secured (e.g., potted) within the precision holes with polished ends of the optical fibers located at end faces of the ferrules. Precise fiber alignment depends on the accuracy of the central hole of each ferrule. Fiber alignment occurs when two ferrules are inserted into an alignment sleeve such that the end faces of the ferrules oppose one another and the optical fibers supported by the ferrules are co-axially aligned with one another. Normally, ferruled connectors use ceramic or metal ferrules in which the precision center holes are drilled. Disadvantageously, drilling of such a central hole that is accurate enough for aligning can be difficult. In addition, a connector containing a ferrule has very high manufacturing costs. Therefore looking for adequate alignment solutions containing ferrule-less connectors would be more desirable.
V-grooves are commonly used in prior-art ferrule-less fiber optic alignment devices. An example is the V-groove method described in U.S. Pat. No. 6,516,131 used for alignment of optical fiber ends. The V-groove is uni-directionally or bi-directionally tapered for enabling easy positioning of the fibers. Optical fibers are pressed into the V-grooves and line contact between the optical fibers and the surfaces of the V-grooves assists in providing precise alignment of the optical fibers. In one example, two optical fibers desired to be optically connected together are positioned end-to-end within a V-groove such that the V-groove functions to co-axially align the optical fibers. End faces of the aligned optical fibers can abut one another.
For optical couplings to be effective, it is important for the end faces of the optical fiber being coupled together to be clean. Improvements are needed in this area.